Ground speed implement height control adjustment rate on agricultural vehicles

ABSTRACT

An adjustable height implement system for an agricultural vehicle. The system includes a harvesting implement having an adjustable height, a control system operably connected to the harvesting implement to adjust the height of the harvesting implement with respect to the ground and a sensor configured to determine a ground speed. The control system alters the rate of the height adjustment in response to the ground speed. A method and agricultural vehicle are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/216,520, filed May 18, 2009.

FIELD OF THE INVENTION

The present invention relates to the height control operation of animplement on an agricultural vehicle. In particular, the inventionrelates to a system and method for adjusting the rate of heightadjustment of an implement on an agricultural vehicle.

BACKGROUND OF THE INVENTION

The operation of most agricultural vehicles requires substantialoperational involvement and control by the operator. For example, in acotton harvester the operator is required to control the direction andspeed of the vehicle while also controlling the height of the harvestingdrum, the amount of harvested crop stored on the vehicle and a varietyof other operation conditions. Accordingly, to reduce the effortrequired by the operator, it is useful to automate as many tasksperformed by the operator as possible.

Conventional cotton harvesters include two or more harvesting implementscommonly supported for vertical movement on a fore-and-aft wheeled frameof the harvester. Each harvesting implement includes a harvestingassembly defining a plant passage and a harvesting mechanism arrangedwithin the housing. As the cotton harvester is driven across the cottonfield, a row of cotton plants passes through the passage, and theharvesting mechanism removes the cotton therefrom. Cotton grows alongthe entire height of the cotton plant. At the lower end, the cottongrows barely off the ground and sometimes on the ground. The harvestingimplements, therefore, follow as close to the ground as possible so asto pick all of the cotton from the plants.

The ground over which the harvester is driven is usually uneven.Accordingly, if the harvesting implement is set for a lowermost point ofdepression on the ground, stalk lifters extending from a forward end ofthe harvesting implement will tend to “dig into” high points of groundcontour. As the harvester is driven across the field, the wheels on theharvester frame ride between adjacent rows of cotton plants. In softermuddy conditions, the wheels of the harvester furthermore deform thefield into slight recesses and valleys or raised ridges. As will beappreciated, proper positioning of the harvesting implement relative tothe ground contour is further complicated in such undulating fieldconditions.

To optimize efficiency during the harvesting operation, cottonharvesters are known to include a harvesting implement height controlsystem for automatically controlling the height of the harvestingimplement relative to the ground contour. The elevation of theharvesting implement is primarily controlled by a lift mechanismactuated in accordance with ground contours. Variations of the groundcontour are sensed by a ground engaging element, such as a shoe, mountedon the harvesting implement in a manner to press on the ground and bepositionally displaced in response to variations of the ground contourprofile.

During the harvesting process for cotton, it is generally necessary tohave the harvesting implements very close to the ground (0.5-3.0 inches)to ensure optimal harvesting. To do this, the height control system mustreact to changes in terrain in a timely manner. Current height controlsystems use a fixed or manually adjustable reaction rate to control theresponse time. Since the average implement or drum is approximately 4feet long and the entire length is needed to ensure optimal harvesting(as opposed to combine headers that only need the front of the header tobe optimized), the optimal height control system for cotton harvestersmust ensure that proper height is maintained for the entire length ofthe implement. Height changes of the implement that are too slow or toofast may result in inefficient harvesting. For example, a dip in terrainat a height rate of ground speed may result in crop that is notharvested during the period of time in which the height adjustment istaking place. In addition, faster changes of height at higher groundspeed provide additional safety for the implement and the vehicle byadjusting to changes in the ground clearance at a greater rate of heightadjustment.

Accordingly, it would be desirable to provide an automated implementheight adjustment arrangement and method that provides a rate of heightadjustment that is related and/or dependent upon the ground speed of thevehicle.

SUMMARY OF THE INVENTION

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate the preferred embodiment of theinvention, and together with the description, serve to explain theprinciples of the invention.

One embodiment of the present invention includes an adjustable heightimplement system for an agricultural vehicle. The system includes aharvesting implement having an adjustable height, a control systemoperably connected to the harvesting implement to adjust the height ofthe harvesting implement with respect to the ground and a sensorconfigured to determine a ground speed. The control system alters therate of the height adjustment in response to the ground speed.

Another embodiment of the present invention includes a method includingproviding an agricultural vehicle having an adjustable height implementsystem. The adjustable height implement system includes a harvestingimplement having an adjustable height, a control system operablyconnected to the harvesting implement to adjust the height of theharvesting implement with respect to the ground and a sensor configuredto determine a ground speed. The method further includes determining aground speed with the sensor and altering the rate of height adjustmentin response to the ground speed determined.

Still another aspect of the present invention includes an agriculturalvehicle. The vehicle includes an adjustable height implement system foran agricultural vehicle. The adjustable height implement system includesa harvesting implement having an adjustable height, a control systemoperably connected to the harvesting implement to adjust the height ofthe harvesting implement with respect to the ground and a sensorconfigured to determine a ground speed. The control system alters therate of the height adjustment in response to the ground speed.

An advantage of embodiments of the present invention includes efficientharvesting, including cotton harvesting, wherein the height at the pointof harvest is adjusted to provide a maximum or near maximum harvestingefficiency.

Another advantage of embodiments of the present invention is a reductionin unnecessary power and strain on the equipment, particularly at lowground speeds.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an agricultural vehicle including a harvestingimplement having an automatically adjustable height.

FIG. 2 is a schematic representation of an embodiment of an implementposition control system.

FIG. 3 is a flow chart illustrating a method according to an embodimentof the invention.

FIG. 4 illustrates an exemplary relationship between rate of heightadjustment and ground speed.

FIG. 5 illustrates another exemplary relationship between rate of heightadjustment and ground speed.

FIG. 6 shows a known exemplary control scheme for an implement headadjustment.

FIG. 7 shows a control scheme according to an embodiment of theinvention for an implement adjustment.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the present preferred embodimentof the control circuit of the invention, examples of which areillustrated in the accompanying drawings. Wherever possible, the samereference characters will be used throughout the drawings to refer tothe same or like parts.

Height control systems on cotton harvesters or other agriculturalharvesters maintain a desired ground clearance and should operate in amanner that minimizes or eliminates potential damage to the implementsor drums. The system of the present invention includes an automatedheight adjustment in response to the ground distance sensors. Thearrangement of automated height adjustment may be any arrangement orsystem known for providing height control in response to the distance tothe ground. “Height”, as used herein is meant to be a unit of distancecorresponding to the distance between a component, such as a harvestingimplement, and the ground. Height is not limited to an absolute numberand may be relative to other components or calculated based on aplurality of measurements. The control system may include sensorsproviding measurements of ground control using physical measurements ordigital signals from optical or other sensors. The control system is notlimited to a fully automated system, but may also include a system thatincludes manual or override adjustments remotely or by the operator. Theautomated height control according to the present disclosure includes acontrol system that is capable of having altering rates of adjustment.That is, the height control system according to the present disclosureincludes a rate of raising or lowering the implement, for example to aheight set point, that may be adjusted to be a greater or lesser rate ofspeed.

The system according to the present disclosure includes known heightsensor arrangements to detect changes in the terrain over which theimplement is moving and calculates the distance between the implementand the ground. The system utilizes the measured or calculated distancefrom the ground to determine the desired height of the implement. Thesystem then obtains the vehicle ground speed. The ground speed may bedetermined using any suitable technique for determining ground speed.The ground speed is determined in order to calculate the rate at whichthe implement should be moved to the desired height. Once the height isdetermined and the rate at which the height adjustment is to be made,then the system adjusts the height of the implement at the determinedrate.

One embodiment includes a cotton harvester. A representative cottonharvesting vehicle 10 is shown in FIG. 1, including a cotton compactingstructure and bin 11 for receiving and holding cotton harvested by aplurality of picker implements 14 arrayed across a forward end ofvehicle 10. The cotton is conveyed from harvesting implements 14 througha plurality of parallel ducts 16 by air flows through the ducts. Thecotton harvester travels along ground 12 and monitors a height of theimplement 14 above the ground 12. Automatic controls provide heightadjustment of implement 14 above ground 12.

FIG. 2 is a schematic representation of the preferred embodiment of theimplement position control system 24. Control system 24 includes amicroprocessor based control unit 26, a man-controller interface 28, avehicle direction and speed control lever 30, a hydraulic control valve32, and an implement lift mechanism 39 (e.g., hydraulic lift cylinders,cable lift arrangements, hydraulic motor and gear arrangements, orelectric motor and gear arrangements).

One or more harvesting implements 14 may be supported at a forward endof frame 13. Each harvesting implement 14 is a conventional structureincluding a fore-and-aft extending housing assembly 18 which rotatablysupports a harvesting mechanism (not shown) and other associatedmechanisms for stripping or picking cotton from the plants as theharvester is driven across the field. A pair of stalk lifters 20 extendforwardly from a housing assembly 18 for guiding the cotton plantsthrough a plant passage defined by the housing assembly 18.

In addition to man-controller interface 28, system 24 also includes araise and lower switch 58 which may be mounted in lever 30. By way ofexample, raise and lower switch 58 is a centrally biased momentarycontact switch. As shown in FIG. 2, man-controller interface 28 iscoupled to unit 26 by a signal bus 60 and switch 58 may be coupled tounit 26 by a signal bus 70.

The control system for providing height control includes a control unit26, man-controller interface 28, control lever 30, and valve 32 as wellas the associated components that cooperatively provide height controlto the implement 14. Control unit 26 is also coupled to ground speedsensor 72 by a signal bus 74. The ground speed sensor 72 may include anysensor or device capable of determining ground speed of the vehicle 10.For example, the ground speed sensor 72 may include a global positioningsystem (GPS) device, a shaft or motor speed indicator or any otherdevice suitable for measuring a parameter suitable for determining orestimating ground speed. The ground speed can be directly measured,calculated or indirectly measured. In addition, the control unit iscoupled to signal receiving assembly 48 by signal bus 73. The signalreceiving assembly 48 provides a ground height measurement that isusable by the control unit 26 to determine the desired height ofimplement 14. The ground height measurement is not limited to thearrangement shown and may include any known arrangement for measuring ordetermining the height of the implement from ground 12.

Control unit 26 is in communication with control valve 32 which includesa raising solenoid 80 and a lowering solenoid 82 to which signal bus 78is connected. Control unit 26 may apply pulse width modulated signals tosolenoids 80 and 82 which allow valve 32 to control the flow of fluidbetween a pressurized hydraulic fluid source 84 and lift device 38. Inthe present embodiment, source 84 is a hydraulic pump connected inseries with a hydraulic fluid storage tank and appropriate filters. Thespecific hydraulic arrangement is not limited. In addition, theinvention is not limited to hydraulic lift mechanisms and may includeelectrical motor lift mechanism, pneumatic systems or any otherarrangement that is suitable for lifting harvesting implements.

A lift mechanism 39, as shown in FIG. 2, is provided for supporting theharvesting implement 14 for vertical movement between lowered and raisedelevational positions. The mounting and supporting system preferablyincludes a lift assembly 27 and an elongated tension arm 29 connected tothe lift assembly.

The lift assembly operates essentially as a parallelogram type linkagewhich is pivotally connected to and extends forwardly from frame 13 ofthe vehicle 10. As illustrated in FIG. 2, the lift assembly 27 includesa pair of laterally spaced upper tension arms 29 extending generallyparallel to a pair of laterally spaced lower lift arms 31, 34. Thetension arms 29 have an effective length which is approximately equal tothat of the lift arms 31 and 34, respectively, and, therefore, theharvesting implements 14 connected thereto are maintained in a generallylevel attitude during field operation as they are moved between lowerand raised elevational positions. The harvesting implements 14 arepreferably individually connected to the tension arm 29 which, asillustrated, is suitably connected to the lift assembly 27.

A pressurized hydraulic system 36 is preferably provided for adjustingthe elevation of the harvesting implement 14. As shown in FIG. 2, thehydraulic system 36 includes hydraulic lift device 38 preferably in theform of linearly distendable hydraulic cylinders connected between theframe 13 and the implement 14. Conduits 40, 42 connect the valve 32 tothe lift device 38.

During a harvesting operation, operation of the lift device 38 andthereby the harvesting elevation of the harvesting implement 14 isautomatically controlled by a harvesting implement height sensing systemgenerally indicated by reference numeral 46. As shown in FIG. 2, theheight sensing system 46 includes a signal receiving assembly 48, asignal transmitting mechanism 50, and a linkage assembly 52interconnecting the signal receiving assembly 48 and the signaltransmitting mechanism 50.

In one embodiment, the signal transmitting mechanism 50 includes aground contour sensing shoe or element 56 pivotally connected to theharvesting implement. The ground engaging element 56 is responsive tothe ground contour and is operable to position control valve 32 withinits range of movement to effect harvester implement elevation correlatedwith the vertical movement of the ground engaging element relative tothe harvesting implement.

FIG. 3 shows a method according to an embodiment of the presentinvention. The method begins when the system for height adjustment rateis activated or as the system is called upon by the control unit 26(step 310). The method first determines whether the automated heightcontrol system is activated (step 312). If the automated height controlsystem is not activated (i.e., “NO” in FIG. 3), the method returns tostep 310. Step 312 may be omitted in certain embodiments. For example,if manual adjustment is being provided, the height adjustment methodaccording to the present invention may still be utilized. If theautomated control system is activated (i.e., “YES” in FIG. 3), themethod then determines whether height adjustment is required (step 314).The determination of whether height adjustment is required can beaccomplished using any suitable method, including any method utilized bythe automated height control system. For example, if the ground heightvalue is determined to be larger than the desired number, the systemwill determine that height adjustment is required. If height adjustmentis not required (i.e., “NO” in FIG. 3), the method returns to step 310.However, if height adjustment is required (i.e., “YES” in FIG. 3), themethod then determines the ground speed (step 316). The ground speed canbe determined using ground speed sensor 72 (see FIG. 2), which mayinclude a global positioning system (GPS) device, a shaft or motor speedindicator or any other device suitable for measuring a parametersuitable for determining or estimating ground speed. The ground speedcan be directly measured, calculated or indirectly measured. Once theground speed is determined, a rate of height adjustment is determined(step 318). The rate of height adjustment is dependent upon the groundspeed determined in step 316. After the rate of height adjustment isdetermined, the height of the implement is adjusted to the desiredheight from the ground at the rate of height adjustment (step 320).

The relationship between the rate of height adjustment and ground speedcan vary with respect to the system on which it is utilized. Therelationship is preferably such that the greater the ground speed, thegreater the rate of height adjustment. As shown in FIG. 4, the rate ofheight adjustment can vary linearly with respect to the ground speed.However, the relationship between height adjustment rate and groundspeed need not be linear and may be a non-linear or a discontinuousrelationship. Another embodiment is shown in FIG. 5 wherein therelationship between height adjustment rate and ground speed may bealtered at different rates at different areas of ground speed. The rateof height adjustment may be a direct input to the control unit, as aparticular speed at which the implement 14 is raised or lowered.Alternately, the rate of height adjustment may be a factor or a variableinput into a control algorithm. The rate of height adjustment may be amultiplier for a control gain or error rate. The resultant controlfunction would result in a height adjustment that is raised or loweredat a rate corresponding to the control algorithm adjusted by themultiplier or factor corresponding to the rate of height adjustmentdetermined for the particular ground speed. For example, the controlunit 26 may include a product/integral/differential (PID) control loopinto which an error signal is passed. In this embodiment, the PIDcontrol loop includes associated gains for each of the components of thecontrol loop. The output for the PID control loop may be used todetermine an output to valve 32. The height adjustment rate may bealtered by multiplying the error and/or control loop gains by a factorcorresponding to ground speed.

FIG. 6 shows a known exemplary control scheme for an implement headadjustment to a set point height 600. In this example, the control unitprovides a set point corresponding to a desired height for the implementfrom the ground. As shown in FIG. 6, the position of the implement isadjusted over time until the height of the implement reaches set pointheight 600.

FIG. 7 shows a control scheme according to an embodiment of theinvention for an implement adjustment to a set point height 600. As inFIG. 6, the control scheme includes a set point height 600 correspondingto a desired height determined by the control unit for the implementfrom the ground. Unlike the control scheme in FIG. 6, the rate at whichthe implement is adjusted is altered with ground speed. As shown in FIG.7, a higher ground speed (i.e., the curves farther to the left on thegraph) results in obtaining set point height 600 in a shorter period oftime. A lower ground speed (i.e., the curves farther to the right on thegraph) results in obtaining set point height 600 in a longer period oftime. As a result, when the vehicle 10 is moving at a greater velocity(i.e., ground speed), the height of the implement 14 is adjusted morequickly to match the desired height so less crop is missed duringharvesting and/or the implement 14 is more quickly pulled up to avoidterrain that may damage the implement. Likewise, the slower adjustmentat lower speeds permits efficient harvesting, while reducing wear on thecomponents.

While the invention has been described with reference to a preferredembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

1. An adjustable height implement system for an agricultural vehiclecomprising: a harvesting implement having an adjustable height; acontrol system operably connected to the harvesting implement to adjustthe height of the harvesting implement with respect to the ground; asensor configured to determine a ground speed; wherein the controlsystem alters the rate of the height adjustment in response to theground speed.
 2. The adjustable height implement system of claim 1,wherein the agricultural vehicle is a cotton harvester.
 3. Theadjustable height implement system of claim 1, wherein the controller iscapable of adjusting the harvesting implement height to a heightcorresponding to a desired height of the harvesting implement inresponse to the height measurement from the harvesting implement to theground.
 4. The adjustable height implement system of claim 1, whereinthe rate of height adjustment in response to ground speed is amultiplier communicated to the control system.
 5. The adjustable heightimplement system of claim 1, wherein the rate of height adjustment inresponse to ground speed is a multiplier to an error rate measurement ofthe control system.
 6. The adjustable height implement system of claim1, wherein the rate of height adjustment is altered linearly withrespect to ground speed.
 7. The adjustable height implement system ofclaim 1, wherein the rate of height adjustment is altered nonlinearlywith respect to ground speed.
 8. A method comprising: providing anagricultural vehicle having an adjustable height implement systemcomprising: a harvesting implement having an adjustable height; acontrol system operably connected to the harvesting implement to adjustthe height of the harvesting implement with respect to the ground; asensor configured to determine a ground speed; determining a groundspeed with the sensor; altering the rate of height adjustment inresponse to the ground speed determined.
 9. The method of claim 8,wherein the agricultural vehicle is a cotton harvester.
 10. The methodof claim 8, further comprising adjusting the harvesting implement heightwith the control system to a height corresponding to a desired height ofthe harvesting implement in response to the height measurement from theharvesting implement to the ground.
 11. The method of claim 8, whereinthe agricultural vehicle is a cotton harvester.
 12. The method of claim8, further comprising communicating the rate of height adjustment inresponse to ground speed to the control system as a multiplier.
 13. Themethod of claim 8, wherein the altering includes adjusting the errorrate to provide a higher or lower rate of height adjustment for theimplement.
 14. An agricultural vehicle comprising: an adjustable heightimplement system for an agricultural vehicle comprising: a harvestingimplement having an adjustable height; a control system operablyconnected to the harvesting implement to adjust the height of theharvesting implement with respect to the ground; a sensor configured todetermine a ground speed; wherein the rate of the height adjustment isaltered by the control system in response to the ground speed.
 15. Theagricultural vehicle of claim 14, wherein the controller is capable ofadjusting the harvesting implement height to a height corresponding to adesired height of the harvesting implement in response to the heightmeasurement from the harvesting implement to the ground.
 16. Theagricultural vehicle of claim 14, wherein the rate of height adjustmentin response to ground speed is a multiplier communicated to the controlsystem.
 17. The agricultural vehicle of claim 14, wherein the rate ofheight adjustment in response to ground speed is a multiplier to anerror rate measurement of the control system.
 18. The agriculturalvehicle of claim 14, wherein the rate of height adjustment is alteredlinearly with respect to ground speed.
 19. The agricultural vehicle ofclaim 14, wherein the rate of height adjustment is altered nonlinearlywith respect to ground speed.